Bone Stress Injury in Runners and the Fuelling Question

You have been building mileage for a few months. At some point the shin, the foot, or the hip started to complain. At first it warmed up and went quiet after the first kilometre. Now it arrives earlier in the run, stays afterward, and there is one spot you can find with a fingertip that is sore to press.

That pattern is worth paying attention to. A bone stress injury is what happens when repeated loading outpaces the bone's ability to repair itself. It is common in runners, it responds well to being caught early, and it tends to come back if the reason it happened never gets addressed.

How a bone stress injury starts and how it escalates

Bone is living tissue. It carries microscopic damage from ordinary loading and clears it through remodelling. Trouble begins when damage accumulates faster than the repair process removes it.

The 2014 commentary by Warden, Davis and Fredericson in the Journal of Orthopaedic and Sports Physical Therapy describes bone stress injury as the inability of bone to withstand repetitive loading, producing structural fatigue with localised bone pain and tenderness. The same paper sets out the progression clearly: a bone stress injury occurs along a pathology continuum that begins with a stress reaction, which can progress to a stress fracture and ultimately to a complete bone fracture.

That continuum is why early symptoms are worth acting on.

A stress reaction is the early end. The bone is irritated and remodelling is struggling to keep up, without a visible fracture line. Symptoms are often mild and easy to run through.

A stress fracture is further along. A crack has formed in the bone. Pain is usually present during activity, often with walking, and the bone is tender to press over a small area.

A complete fracture is the end of the continuum. It is uncommon in runners who act early, and it is one reason a painful femoral neck or a painful front of the shin is taken seriously rather than watched.

The clinical tell most runners describe is a change in how the pain behaves rather than how much it hurts. Pain that used to appear at kilometre five now appears at kilometre two. Pain that used to settle within an hour now sits there through the evening.

The 2014 paper also notes that bone stress injuries recur often, which is why the plan has to cover the cause and the healing both. Rest alone treats the episode and leaves the reason intact.

Why the location changes everything

Two runners can have the same symptom, the same pain level, and the same training history, and need completely different management, because the injury sits in a different bone.

The 2022 review of bone stress injuries in Nature Reviews Disease Primers, written by Hoenig, Ackerman, Warden and colleagues, states the principle directly: management of bone stress injuries is guided by their location and the consequent risk of healing complications. Bone stress injuries at low-risk sites typically heal with activity modification followed by progressive loading and return to activity. Additional approaches including non-weight-bearing immobilisation, medications or surgery are usually limited to injuries at high-risk sites.

Low-risk sites include most of the shaft of the tibia, the shaft of the fibula, and most of the metatarsals. Blood supply is good, the loading pattern tends to compress the bone rather than pull it apart, and healing is generally reliable with reduced loading followed by a graded build back.

High-risk sites include the femoral neck at the top of the thigh bone, the front surface of the tibia, the navicular in the middle of the foot, and the sacrum at the base of the spine. These sites carry a higher chance of delayed healing, of the injury not healing at all, or of progressing to a complete fracture. They are handled more conservatively from the start, often with a period of protected or non-weight-bearing loading, and sometimes with a surgical opinion.

The practical consequence is worth stating plainly. Groin or front-of-hip pain in a runner building mileage, one-sided buttock or low back pain that is worse on impact, or a persistent ache in the middle of the top of the foot are all worth assessing sooner rather than later, because each points at a high-risk area. Waiting out the pain is a reasonable instinct and the wrong one for those sites.

Shin pain is where the distinction matters most, because two different problems live in the same place. A diffuse ache spread over several centimetres along the inside border of the shin often points toward medial tibial stress syndrome, covered in shin splints and medial tibial stress syndrome in runners. Pain that narrows to a single tender point, particularly on the front surface of the tibia, is treated as a bone stress injury until proven otherwise.

What in your training actually caused it

Bone stress injuries are load errors. The 2021 review by Warden, Edwards and Willy in Current Osteoporosis Reports frames every bone stress injury in runners as an error in workload, where the interaction between the number and the size of the loading cycles exceeds the ability of the tissue to resist the repeated loads. Two variables sit inside that: how many times the bone is loaded, and how hard each load is.

The patterns that show up repeatedly in a running history:

• Volume that climbed faster than the bone adapted. Muscle and fitness adapt in weeks. Bone adapts over months. A build that feels fine to the cardiovascular system can still be ahead of the skeleton.
• A change in surface, shoe, or terrain. Moving from trail to pavement, or changing to a different shoe, shifts where and how the load lands.
• Added intensity on top of existing volume. Speed work, hills, and races raise the size of each loading cycle. Adding them without pulling back elsewhere raises total stress.
• Too little recovery between hard sessions. Remodelling needs time. Back-to-back hard days compress the window in which repair happens.
• A return from time off that resumed at the old volume. Bone detrains during a break. Picking up where you left off is a common route into this injury.

The 2014 JOSPT commentary lists intervention targets beyond reducing mileage: training-programme design, reducing impact-related forces (for example instructing a runner to run more softly or with a higher stride rate), and improving the strength and endurance of the local muscles, such as the calf for tibial injuries and the small muscles of the foot for metatarsal injuries. Muscles that fatigue late in a run stop absorbing load, and the bone takes more of it.

Runners preparing for a spring goal race often arrive at this injury during a winter build. The pacing principles in our marathon injury prevention and return to running guide apply directly.

The fuelling side, and why it matters for bone

Training load is one half of the story. How much total energy a runner takes in relative to what training burns also affects the biology of bone repair.

The term for this is low energy availability, meaning the energy left over for the body's basic functions after training has taken its share. When that stays low over time, a range of body systems are affected, and bone is one of them.

The 2023 International Olympic Committee consensus statement on Relative Energy Deficiency in Sport, published in the British Journal of Sports Medicine by Mountjoy and colleagues, describes REDs as a syndrome of health and performance outcomes in female and male athletes exposed to low energy availability, meaning inadequate energy intake relative to exercise energy expenditure. The 2023 update notes the growing role of low carbohydrate availability, the interplay between mental health and REDs, and more data on how low energy availability affects males.

Several things are worth saying clearly here.

This affects men. The older framing centred on women and on menstrual changes, and it left a generation of male runners out of the conversation. The IOC statement explicitly covers female and male athletes, and points to more evidence on the effect of low energy availability in males. A male runner with a bone stress injury and a heavy training load deserves the same questions.

Low energy availability has several routes. It can arrive through an underestimated appetite during a hard build, a busy schedule where meals get skipped, a period of high stress, a change in training load without a matching change in intake, or a deliberate attempt to lose weight. It can also arrive through disordered eating. The IOC statement describes low energy availability on a spectrum that ranges from adaptable to problematic.

Nobody is going to moralise about your food. The useful clinical question is whether intake is matching the current training load, and what to adjust if it is falling short. That is a practical problem with practical answers.

The right professional for the nutrition side is a registered dietitian. Dietitians in British Columbia are regulated by the College of Health and Care Professionals of BC, the same college that regulates physiotherapists. A physiotherapist can ask the screening questions and can flag a pattern, and the assessment and plan for intake belong with a dietitian. We cover what a dietitian contributes during recovery in nutrition and injury recovery.

If disordered eating is part of the picture, the care team is larger. That situation needs a physician and a mental health professional, which sits outside physiotherapy scope. A therapist who notices the pattern and says so plainly, without judgement, has done the right thing by passing it to the people equipped to help.

The IOC statement also introduced a clinical assessment tool, now in its second version, that helps a clinician work through detection and risk stratification. Your physician or a sports medicine doctor is the person who uses it.

When imaging is needed

Not every suspected bone stress injury needs a scan. The Nature Reviews Disease Primers review describes diagnosis as a combination of patient history and physical examination, with imaging used for confirmation. That order matters: the history and the hands-on examination come first, and imaging confirms rather than discovers.

Imaging becomes more useful when:

• The suspected site is a high-risk one. Femoral neck, front of the tibia, navicular and sacrum are treated differently, so knowing what is there changes the plan.
• The diagnosis is unclear after assessment, or symptoms do not fit a straightforward pattern.
• Symptoms have not settled on a sensible reduction in loading over a reasonable stretch of time.
• A decision with real consequences depends on the answer, such as whether to continue training toward a goal race.

One practical point about the type of scan. A plain X-ray is often normal in the early stages, because the changes it shows take time to appear, so a normal X-ray does not rule the injury out. MRI is the more sensitive test and is usually requested when the answer matters clinically. Ordering imaging is a physician's decision, so this is a conversation for your family doctor or a sports medicine physician.

Runners with a history of several bone stress injuries, or with other risk factors for reduced bone density, may also be sent for bone density testing. That is a physician's call as well.

How the return to running is staged

The goal of the return is to rebuild the bone's tolerance for repeated loading, so the same injury does not arrive again in three months. Being pain-free at rest is an early milestone along the way.

A typical progression moves through phases, and the timing of each depends on the site, how far along the continuum the injury was, and how the tissue responds.

Offload and maintain fitness. Running comes down or stops, with the amount depending heavily on the site. Cross-training that keeps the cardiovascular system going without loading the injured bone fills the gap: cycling, swimming, deep-water running, or an elliptical, chosen by what the specific injury tolerates.

Rebuild capacity while it heals. Strength work for the muscles around the injured area continues through this phase, aimed at the local musculature the 2014 JOSPT commentary identifies, along with general lower-limb and hip strength. This is the part runners skip, and it is a large part of why the injury recurs.

Reintroduce walking and impact. Pain-free walking comes before running. Some plans use a walk-run structure, some use short easy runs on alternate days, and symptoms guide the progression.

Build volume before intensity. Easy running gets rebuilt first. Speed work, hills and long runs return after the base is re-established, one variable at a time.

Address what caused it. Training design, recovery days, running form where it is relevant, strength, and the fuelling side. Without this, the injury tends to return.

Timelines are individual. A low-risk stress reaction caught early behaves differently from a navicular stress fracture, and the same injury heals at different speeds in different people. Your therapist will set expectations after the assessment and revise them as the tissue responds.

What a first visit looks like

A first physiotherapy assessment starts with the training history in detail. Your therapist will ask what your weekly volume has been over the last two to three months, what changed and when, what surfaces and shoes you use, how the pain behaves within a run and afterward, and whether you can find a specific tender point.

They will ask about fuelling and recovery too: how meals fit around training, how sleep has been, whether weight has changed, and for female runners, whether the menstrual cycle has changed. Those are screening questions asked of every runner with a suspected bone stress injury, and they are asked without judgement.

The physical examination looks at the tender area, tests how the bone responds to load, and assesses the strength and control of the hip, knee, ankle and foot. Your therapist may recommend you see a physician for imaging before the plan goes further, which is standard for a suspected high-risk site.

Physiotherapy is a direct-access profession in British Columbia, regulated by the College of Health and Care Professionals of BC, so no physician referral is needed to book an assessment. Some extended-health plans require a referral for reimbursement, so check with your insurer first.

Expect the first plan to be specific about what to stop, what to keep doing, and what to add. Maintaining fitness and rebuilding strength happen during the healing period rather than after it.

When to see a doctor first

Book with your physician rather than waiting for a physiotherapy appointment if you have groin or front-of-hip pain that hurts when you walk or bear weight, since a femoral neck bone stress injury carries real consequences if it progresses. The same applies to pain over the front of the shin or the middle of the top of the foot that has persisted despite reduced running.

Seek prompt medical assessment for a sudden severe increase in pain, an inability to bear weight, night pain that wakes you, or pain with fever or unexplained weight loss. Those patterns need a medical opinion rather than a rehabilitation plan.

Runners who have had several bone stress injuries, who have a history of an eating disorder, or who have lost their menstrual period should see a physician about the broader picture. Repeated bone stress injuries in a runner are a signal to look at bone health and energy availability, and that assessment starts with a doctor.

This article is general information, not personal medical advice. A regulated practitioner can confirm whether the patterns described apply to you.

Frequently asked questions

What is the difference between a stress reaction and a stress fracture?

They are two points on the same continuum. The 2014 JOSPT commentary by Warden, Davis and Fredericson describes bone stress injury as beginning with a stress reaction, which can progress to a stress fracture and ultimately to a complete bone fracture. A stress reaction means the bone is irritated and remodelling is falling behind, without a visible fracture line. A stress fracture means a crack has formed. Catching it at the reaction end usually means a shorter and simpler recovery.

How do I know if my shin pain is shin splints or a stress fracture?

The main difference is how the pain is distributed. Medial tibial stress syndrome, commonly called shin splints, usually produces a diffuse ache spread over several centimetres along the inside border of the shin. A bone stress injury tends to narrow to one tender spot you can find with a fingertip, worsens as the run goes on, and often lingers after the run. Pain on the front surface of the tibia is treated as a bone stress injury until an assessment says otherwise, because that is a high-risk site.

Which bones are considered high-risk sites?

The femoral neck at the top of the thigh bone, the front surface of the tibia, the navicular in the middle of the foot, and the sacrum at the base of the spine. The 2022 Nature Reviews Disease Primers review on bone stress injuries explains that management is guided by location and the consequent risk of healing complications, with high-risk sites sometimes needing non-weight-bearing immobilisation, medication or surgery. Low-risk sites typically heal with activity modification followed by progressive loading.

Why are high-risk and low-risk sites treated differently?

Because the chance of something going wrong during healing differs by site. High-risk sites carry a greater chance of delayed healing, of the bone not healing, or of progression to a complete fracture, which is why they are managed more cautiously from the start. Low-risk sites generally heal reliably with a period of reduced loading and a graded return. The difference relates to blood supply and to whether the loading pattern at that site tends to compress the bone or pull it apart.

Do I need an MRI to diagnose a bone stress injury?

Not in every case. The 2022 Nature Reviews Disease Primers review describes diagnosis as a combination of patient history and physical examination, with imaging used for confirmation. Imaging becomes more useful when a high-risk site is suspected, when the diagnosis is unclear, or when symptoms have not settled on reduced loading. A plain X-ray is often normal early on, so a normal X-ray does not rule the injury out. Ordering imaging is a physician's decision.

What is Relative Energy Deficiency in Sport?

REDs describes a set of health and performance effects in athletes exposed to low energy availability, meaning energy intake that is inadequate relative to the energy used in exercise. The 2023 International Olympic Committee consensus statement in the British Journal of Sports Medicine covers female and male athletes and describes low energy availability as existing on a spectrum from adaptable to problematic. It is a syndrome assessed by a physician, often alongside a registered dietitian.

Does low energy availability only affect women?

No. The 2023 IOC consensus statement explicitly addresses female and male athletes, and notes that more data have emerged on the effects of low energy availability in males since the previous consensus. The older framing focused on women and on menstrual changes, which left male runners out of the conversation for a long time. A male runner with a bone stress injury and a heavy training load should be asked the same questions.

Does this mean I have an eating disorder?

No. Low energy availability can arise without any disordered eating: appetite that does not keep pace with a hard training build, meals missed in a busy week, a period of high stress, or an increase in training without a matching increase in intake. The IOC statement describes low energy availability on a spectrum from adaptable to problematic. Where disordered eating is part of the picture, the right care involves a physician and a mental health professional, which sits outside physiotherapy scope.

Should I see a dietitian?

For the nutrition side of a bone stress injury, a registered dietitian is the right professional. Dietitians in British Columbia are regulated by the College of Health and Care Professionals of BC, the same college that regulates physiotherapists. A physiotherapist can screen for the pattern and flag it, and the assessment of intake and the plan to correct it belong with a dietitian. Many extended-health plans cover dietitian visits, so it is worth checking your coverage.

How long until I can run again?

It depends on the site, how far along the continuum the injury was when it was caught, and how your body responds. A low-risk stress reaction found early behaves differently from a navicular stress fracture, and two people with the same injury can heal at different speeds. Your therapist will set expectations after assessing you and revise them as the tissue responds. Be cautious of anyone offering a fixed timeline before an assessment.

Can I cross-train while it heals?

Usually yes, and maintaining fitness is part of a good plan. The specific options depend on what the injured bone tolerates, and choices commonly include cycling, swimming, deep-water running, or an elliptical. Strength work for the muscles around the injured area also continues during this phase, since rebuilding that capacity is part of preventing a recurrence. Your therapist will tell you which activities are safe for your specific injury.

Do I need a referral to see a physiotherapist in BC?

No. Physiotherapy is a direct-access profession in British Columbia, regulated by the College of Health and Care Professionals of BC, so you can book an assessment without a physician's referral. Some extended-health insurance plans require a referral for reimbursement even though the profession does not, so confirm with your insurer before your first visit. If a high-risk site is suspected, your therapist may recommend you also see a physician for imaging.

Sources

• Warden, Davis and Fredericson, "Management and prevention of bone stress injuries in long-distance runners," Journal of Orthopaedic and Sports Physical Therapy, 2014, volume 44, issue 10, pages 749 to 765
• Hoenig, Ackerman, Beck, Bouxsein, Burr, Hollander, Popp, Rolvien, Tenforde and Warden, "Bone stress injuries," Nature Reviews Disease Primers, 2022, volume 8, article 26
• Warden, Edwards and Willy, "Preventing Bone Stress Injuries in Runners with Optimal Workload," Current Osteoporosis Reports, 2021, volume 19, issue 3, pages 298 to 307
• Mountjoy et al., "2023 International Olympic Committee's (IOC) consensus statement on Relative Energy Deficiency in Sport (REDs)," British Journal of Sports Medicine, 2023, volume 57, issue 17, pages 1073 to 1097
• College of Health and Care Professionals of BC, physical therapist scope of practice
• College of Health and Care Professionals of BC, dietitian scope of practice